BETAMETHASONE VALERATE- betamethasone valerate aerosol, foam
Perrigo New York Inc
For Dermatologic Use Only
Not for Ophthalmic Use
Rx Only
DESCRIPTION
Betamethasone Valerate Foam, 0.12% contains betamethasone valerate, USP, a synthetic corticosteroid, for topical dermatologic use. The corticosteroids constitute a class of primarily synthetic steroids used topically as anti-inflammatory agents.
Betamethasone valerate is 9-fluoro11�,17, 21-trihydroxy-16�-methylpregna-1, 4-diene-3, 20-dione 17-valerate, with the empirical formula C27 H37 FO6 , a molecular weight of 476.58. The following is the chemical structure:
Betamethasone 17-valerate
Betamethasone valerate
Betamethasone valerate is a white to practically white, odorless crystalline powder, and is practically insoluble in water, freely soluble in acetone and in chloroform, soluble in alcohol, and slightly soluble in benzene and in ether.
Betamethasone Valerate Foam, 0.12% contains 1.2 mg betamethasone valerate USP, per gram in a thermolabile hydroethanolic foam vehicle consisting of cetyl alcohol, citric acid, ethanol (60%), polysorbate 60, potassium citrate, propylene glycol, purified water, and stearyl alcohol pressurized with a hydrocarbon (propane/butane) propellant.
CLINICAL PHARMACOLOGY
Like other topical corticosteroids, betamethasone valerate foam has anti-inflammatory, antipruritic, and vasoconstrictive properties. The mechanism of the anti-inflammatory activity of the topical steroids, in general, is unclear. However, corticosteroids are thought to act by the induction of phospholipase A2 inhibitory proteins, collectively called lipocortins. It is postulated that these proteins control the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes by inhibiting the release of their common precursor arachidonic acid. Arachidonic acid is released from membrane phospholipids by phospholipase A2 .
Pharmacokinetics
Topical corticosteroids can be absorbed from intact healthy skin. The extent of percutaneous absorption of topical corticosteroids is determined by many factors, including the vehicle and the integrity of the epidermal barrier. Occlusion, inflammation and/or other disease processes in the skin may also increase percutaneous absorption.
The use of pharmacodynamic endpoints for assessing the systemic exposure of topical corticosteroids is necessary due to the fact that circulating levels are well below the level of detection. Once absorbed through the skin, topical corticosteroids are handled through pharmacokinetic pathways similar to systemically administered corticosteroids. They are metabolized, primarily in the liver, and are then excreted by the kidneys. In addition, some corticosteroids and their metabolites are also excreted in the bile.